Preparation And Application Of High Temperature Resistant Silica Aerogel Composite Materials For Space Exploratio

SiO₂ aerogel material has the characteristics of high porosity,low density and so on,making it a kind of light and efficient thermal control material.However,at present,the temperature resistance of silica aerogel material is only 800℃,which leads to the shrinkage and collapse of nanostructures at high temperature,greatly reducing the heat insulation performance,and seriously affecting the working efficiency and working life of power supply.Based on the above problems,this paper discusses the preparation of high temperature resistant（1100℃）aerogel and aerogel composite materials,through the customization of nano size,reduce the shrinkage of silicon particles,in order to ensure its excellent high temperature resistance at the same time,has excellent thermal insulation performance,and by adding reinforcement to improve the mechanical properties and high temperature resistance of aerogel.（1）Research on sol-gel technology of high temperature resistant SiO₂aerogelTo select suitable silicon source,it is necessary to have suitable gel conditions,which can form nanoscale network structure under controllable conditions.The particle size in the silicon source is larger to ensure that the aerogel prepared has a relatively robust skeleton.To study the amount of catalyst and design the experiment,it is required not only to realize the gel but also to have enough operation time to set aside the process window for the subsequent preparation of aerogel composite materials.Aerogels with different densities were selected for preparation.After heat treatment at different temperatures,the aerogel related properties were characterized and the most appropriate aerogel parameters were selected.（2）Preparation and performance optimization of high temperature resistant SiO₂aerogel compositesBy investigating the characteristics of different kinds of reinforcement,select the reinforcement that can meet the requirements of mechanical properties,temperature resistance and heat insulation properties,and prepare aerogel composites with different reinforcement.The related properties of aerogel composites with different reinforcement were characterized.The best fiber reinforcement was selected by comprehensive comparison of various properties.The aerogel composites were prepared by the reinforcement with different carbon fiber content.The thermal conductivity of the aerogel composites was characterized to obtain the appropriate carbon fiber content and select the best composite scheme.（3）Application of high temperature resistant SiO₂aerogel composite in isotope power supplyCombined with the isotope power supply test,the thermoelectric conversion efficiency can be improved to reduce the heat leakage at the cold end,the temperature changes on both sides of the high temperature multilayer are tested,and whether the high temperature resistant SiO₂aerogel composite meets the requirements is investigated.Through the test data of the isotope power supply test,a feasible scheme is provided for the thermal insulation material of isotope power supply in the future.Through the above research process and scheme,the high temperature resistant SiO₂aerogel composite material is finally obtained,which can be applied in vacuum environment at1100℃,and has good mechanical properties,heat insulation properties and high temperature resistance,meeting the requirements of power supply test.